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On this webpage you will find out about:
  • the climate of hot deserts
  • the soil of hot deserts
  • the vegetation and how it is adapted its environment

Video on the desert biome - no narration -
http://www.bbc.co.uk/learningzone/clips/images-of-a-hot-desert-biome-no-narration/3206.html

The climate
  • Daytime temperatures can get up to over 40 degrees in the summer. But it can get very cold at night (below freezing), because there's no clooud to keep the heat in. There is a big daily temperature range
  • It has less than 250mm of rain a year. It might not rain for months or years. When it does it is often in the form of a torrential downpour
  • There are two seasons - summer, when the sun is high in the sky and its very hot and winter when, although it's very warm compared to the UK, it's cooler than the desert summer

Soils
  • Desert soils are rocky, sandy and grey in colour
  • They are thin, and can have a crus caused bu the impact of the infrequent heavy rainfall
  • Evaporation draws water up through the soil, leaving salts deposited near the surface
  • The soil is dry, but it can soak up water quickly when it rains

Vegetation
  • The vegetation has adapted to survive in the harsh desert climate - below is a diagram showing the stratification of the desert vegetation:
Desert_strat.jpg
Desert yellow daisy - small linear leaves that are hairy and slightly succulent. Seeds are dropped at the end of the dry season on the surface of the soil. When it rains the seed germinate to grow new plants
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Great basin sagebrush - tap roots up to 25m long and small needle-like leaves to reduce water loss
Giant saguaro cactus - roots very close to the surface so that it can soak up water before it evaporates. Outside skin is pleated so that it can expan when water is soaked up. Gorws very slowly.
saguaro19053[1].jpg





Joshua tree - needle-like leaves coated with waxy resin
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Key terms:

Arid: dry conditions typically associated with deserts
Hot deserts: regions of the world with rainfall less than 250mm per year